We plan to continue to study tumor related changes of intestinal epithelial cells with special emphasis on the changes in the structure, function and biosynthesis of cell membranes. These studies will involve comparisons of the membranes of undifferentiated crypt cells, mature villus cells as well as of fetal, adult and malignant intestinal cells. These studies will involve human intestinal cancer and that experimentally produced in animals. Experiments will be carried out on changes in nutrient uptake and transport by malignant cells of the intestinal tract using both human and experimentally produced rat intestinal tumors. Transport will be studied using membrane vesicles derived from intestinal cell microvilli. These observations will be compared to studies in a more controlled tissue culture system using chick embryo cells. Glycoprotein and glycolipid structure and biosynthesis will be studied in fetal, adult and malignant intestinal cells. Further investigations will be carried out to study human fetal-specific and human tumor concanavalin A reactive proteins such as galactosyltransferase. These will be compared to carcino-embryonic antigen (CEA). We hope to pursue studies on the value of and use of serum galactosyltransferase as an aid to the diagnosis of intestinal malignancy.